1. Field of the Invention
The present invention relates to an ambulatory physiological signal measurement apparatus employing a disposable electrode such as 24 hr electrocardiogram monitor (e.g., ECG Holter monitor). In particular, the present invention relates to an electrode-connector used in the ambulatory physiological signal measurement apparatus, an electrode-connector protecting cap for preventing noise from being occurred due to external contact and impact, and an electrode-connector including the same.
2. Discussion of Related Art
An electrode is attached to a skin of a subject, which is connected to a physiological signal measurement apparatus through long wire to measure the physiological signal. In this case, the long wire causes motion artifacts in the physiological signal measurement apparatus. In addition, when the long wire is pulled, impedance between the skin of the subject and the metal electrode is changed, which causes noise-mixed signals in the physiological signal measurement apparatus.
Various approaches have been proposed to solve the above-mentioned problems. S. Pat. No. 5,978,693 entitled “apparatus and method for reduction of motion artifact” to Patrick S. Hamilton, Michael G. Curley, and Roberto M. Aimi, (issued in 1999) teaches a method that attaches a strain gauge to a foam pad and detects separate motion artifacts to thereby reduce the motion artifacts from its original signal.
Other method for reducing the motion artifact has been disclosed in U.S. Pat. No. 4,757,817 to James W. Healy. In this method, some portions of a foam pad on which a rectangular disposable electrode is placed are cut to place a connector wire between the some portions, so that it can be securely held. The wire and the electrode may be securely held, however, electrode-connecter portion is exposed, so that it may cause noise when direct contact or impact is applied to the electrode-connecter portion.
Another method has been disclosed in U.S. Pat. No. 4,503,860 to Marvin W. Sams, and Samuel L. Wasson. This method discloses an anchoring pad below an electrode to prevent electrode and connector wire from being moved. The anchoring pad acts to be securely attached to a skin of a subject by making the bottom surface of the anchoring pad flat and sticky. The electrode-connecter portion is also exposed, so that it may cause noise when direct contact or impact is applied to the electrode-connecter portion.
Above-mentioned methods have improved a motion artifact removal effect a little, however, when they are applied to an apparatus such as an ambulatory physiological signal measurement apparatus that can be attached to a body, the noise occurred from stimulus or impact due to a contact between the electrode and the connector can not be reduced. Furthermore, most of the related arts should design or make a new electrode, which causes an additional cost and inconvenience.